The aim of this study was to determine if cytokeratins (CKs) 8 and 18 - typical epithelial cell markers - are expressed in human corneal endothelium. Cryosections, paraffin-embedded sections and corneal endothelial imprints obtained from eleven corneal discs were used.
Different fixative solutions were applied before indirect immunofluorescent or enzymatic staining. Antibodies against CK8, CK18 and CK8/18 were used and semi-quantitative RT-PCR and Western blotting were performed.
Approximately 50% of the corneal endothelial cells were positive for CK8, CK18 and the CK8/18 after acetone fixation. No signal was detected when 4% formalin or 10% paraformaldehyde was used.
CK8 and CK18 were detected in the endothelium of all tested corneas by Western blotting or semi-quantitative RT-PCR, respectively. We detected CK8 and CK18 in the endothelium of all specimens.
These results clearly demonstrate that cells of the corneal endothelium express CKs 8 and 18 and share some features with simple epithelia.